Modern automobiles are equipped with an impressive number and variety of sensors. For example, cars are now routinely equipped with arrays of ultrasonic sensors to monitor the distance between the car and any nearby persons, pets, vehicles, or obstacles. Due to environmental “noise” and safety concerns, each of the sensors may be asked to provide tens of measurements each second while the car is in motion. As the car industry moves towards the production of autonomous vehicles, the number of sensors (and sensor measurement rate) is expected to increase substantially, placing an ever-growing burden on the communications buses conveying sensor measurements to the electronic control unit (ECU) and/or other processing modules responsible for converting the measurements into situational information and control decisions. The communications burden may be exacerbated by the desire of many manufacturer for “sensor fusion”, which requires communication of relatively raw measurement information to a central processing unit in a fashion that enables the processing unit to combine measurements from multiple sensors. Such combining can enable novel, improved, and/or more robust measurements to be obtained via, e.g., triangulation, inversion, and multi-modal acquisition.
When designing to accommodate increased communications burdens, certain countervailing considerations come into play. Reliability is preferably maximized while minimizing costs of materials, minimizing complexity, minimizing electromagnetic interference (EMI). Thus, for example, it is undesirable to add additional bus conductors or to raise the spectral energy content of signals where that might increase electromagnetic emissions and susceptibility to interference.